Abstract
The crystallization transition of an undercooled monodisperse Lennard-Jones fluid in the presence of small pre-structured seeds is studied with transition interface path sampling combined with molecular dynamics simulations. Compared to the homogeneous crystallization, clusters of 13 particles arranged into a face-centered cubic structure enhance the crystallization rate by one order of magnitude, while icosahedrally ordered seeds do not change the reaction rate at all. We identify two distinct nucleation regimes —close to the seed and in the bulk. Crystallites formed close to the seed attach to it, if it has face-centered cubic structure, and grow around the seed, if its structure is icosahedral.